A demand for coffee roasters for home use has been on the rise in response to growing number of devoted coffee drinkers who desire the flavor of freshly roasted coffee. These home coffee roasters typically have a heating element and a fan for directing hot air into a roasting chamber where the coffee beans are roasted as they are blown around by a hot air stream. The controls on these roasters typically include a variable timer that allows beans to be roasted at a constant temperature for a prescribed time. Coffee beans come in different densities and have varying moisture content. As a result, roasting coffee beans at a constant temperature for a prescribed time, as in conventional coffee roasters, do not always result in consistent and fully developed flavor that coffee enthusiasts desire.
There are coffee roasters that have more than one roasting stages, where coffee beans are roasted, for example, at one temperature for some time and at another temperature for a certain other time period. These roasters, however, do not have the means for maintaining the desired roasting temperature when the ambient temperature varies. Depending on the ambient temperature in which the roaster is operated, there could be a significant temperature variation in the roasting chamber from the desired temperature. For example, some users are known to place the coffee roaster outside the home during use, so as not to have smoke from the roaster fill the inside the house. In such a situation, the temperature inside the roasting chamber may not be at the desired temperatures, resulting in the beans being over or under roasted.
Known coffee roasters have motors that drive the fan at a relatively high RPM. Consequently, the noise level generated by the coffee roaster can be of nuisance. On the other hand, coffee roasters with motors that operate at low RPM have a low noise level and may increase motor life. However, the airflow generated by these roasters is sufficient to mix and roast only a small amount of coffee beans. Also, coffee roasters that are intended for home use are relatively small, so as to be aesthetically attractive to consumers. As a result, the amount of beans that can be roasted are also constrained by the size of the roasting chamber of the roaster. Another disadvantage of known roasters is that they generate uncomfortable amount smoke.